Tag Archives: fly

Let’s start with a short pre-blog quiz: which of these native insects pollinate plants?

bees

moths

beetles

all of the above — plus flies, wasps, butterflies, moths

The answer? #4. If you left out flies and wasps because they freak you out … well, just know there’s scads of different wasps and flies — not to mention bees, moths, and beetles — that’ll pollinate your posies, not to mention your apples and pears, your melons and cukes.

Male carpenter bees seem to help protects nests. Get too close and they’ll act aggressive — even though they don’t have stingers. Females could sting but won’t unless you start handling them.

Let’s look at bees first — native bees! Because the natives outnumber honey bees (originally imported from Europe) in apple orchards. A NYS IPM-funded study from 2009 – 2011 found 102 species of native bees busily pollinating apple flowers — and Cornell’s Bryan Danforth, who led that study, estimates that the native bees outperform honeybees by 200 to 300 percent. Yes, honeybees have a value-added bonus: honey rang the registers in New York at over $10 million in 2015. But if apples or pears (or blueberries or strawberries) are your crop of concern, look to the natives.

Think fruit growers are the only ones to benefit? Dairy farmers take note — leaf-cutter bees pollinate your alfalfa, according to Cornell’s Emma Mullen at NYS IPM’s pollinator conference in 2015. And while many vegetable crops are wind- or gravity-pollinated, key crops like melons, squash, pumpkins and cukes need a pollinators’ help.

Syrphid flies? Harmless. This one’s looking for a flower to pollinate.

So … what about flies? More than meets the eye. Finding New York-specific info is a struggle, so let’s just note that vast numbers of fly species all over the world make their living off nectar. Spreading pollen around is a sideline for them but critical for us. In fact, ecologist Alison Parker (University of Toronto) modeled how bees and flies visit flowers — and showed that lots of bees might not always benefit the flowers because bees take so much pollen. But in this computer model, pollination increased with each fly visit.

Not only that, but with some (perhaps many), their larvae serve as biocontrols for crop-damaging aphids. Most nectar-guzzling flies resemble bees or wasps — after all, if you’re harmless but you look like something that defends yourself with a stinger, you’re more likely to be left alone.

What about beetles, moths, butterflies? Beetles were the very first insect pollinators, with ancient evolutionary origins — and according to the US Forest Service, a global pollination rate of 88 percent. The butterflies and moths? Ranking their value is a tough call, but hey — they have a job; they show up. Actually, those second-shift moths way outnumber day-duty butterflies. But you don’t often see them at work, so we don’t know how much good they do, especially since sometimes their larvae can be troublesome for certain plants.

How about wasps? If you’ve done enough noodling around online to see that wasps do little in the way of pollination because their bodies are hairless, unable to capture and carry much pollen, keep looking. No, they’re not as competent as bees. But many do have hairy bodies, and they do help. Plus they’re great garden predators, tackling all sorts of pests.

Bringing it all together, a NYS IPM-funded project now underway at the State University of New York at Cobleskill will evaluate the efficacy of different native plant combinations in attracting native pollinators of every stripe and color — and invite visitors to view the farm and orchard demonstration plots to learn more.

What to worry about? Well, yes, the big bruisers in the pollination game often have stingers, and we don’t like being stung — but that’s for another post. And of course there’s the issue of bee health and bee declines — again, for another post. No, there’s a couple of somethings that over time could take a toll on any number of critters and plants, and we’re just beginning to wrap our arms around them. One: the impact that changing climates could have on pollinators. Not that we understand the dynamics well. The other: lost and fragmented habitats.

If you go back to Emma Mullen’sslides, you’ll see that bumble bees, for one, are unable to track climate change. And they are not alone. You’ll also find references for habitat loss and fragmentation and if you’re so inclined, you can watch the video of her talk.

More than enough info for now, no? Stay tuned — this is a perennial topic.

Insects exhibit a variety of behaviors or adaptations that help them to survive the harsh conditions of winter. One that can be quite frustrating to homeowners belongs to the the group of insects we call “overwintering pests.” These organisms survive winter by taking refuge in South or West facing cracks and crevices, which maximizes exposure to the warm sun and buffers them from wind and freezing cold. While trees and rocky hillsides provide overwintering sites in nature, man-made structures that now dominate the landscape are perfectly acceptable to these insects.

The Culprits. Multicolored Asian ladybird beetles, boxelder bugs, western conifer seed bugs, cluster flies, and the brown marmorated stink bug are common fall invaders in the Northeast. Some of these insects are exotic invasive species that were accidentally introduced to the US, such as the stink bug, which was first identified from samples collected in Allentown, Pennsylvania in the 1990’s. A new insect, the kudzu bug, was introduced to Georgia in the early 2000’s and may soon invade homes in the Northeast.

Brown Marmorated Stink Bug [note the light and dark bands along the edge of the body]

Can they be Stopped? If overwintering pests gain access to buildings through cracks and crevices, it seems reasonable that sealing these openings will keep pests out. While no formal research has tested this hypothesis, a recent grant awarded by the Pest Management Foundation will evaluate the effectiveness of exclusion as a technique to keep stink bugs and other overwintering pests out of homes (Note: the Pest Management Foundation is the education, research and training arm of the National Pest Management Association). In the mean time, below are some common recommendations to dealing with overwintering pests:

Using an appropriate sealant labeled for doors and windows, seal exterior gaps that could allow entry into the home. Remember to inspect locations where wires, pipes, and other utility lines enter the structure, especially on the South and West facing side of buildings.

Look for and seal gaps around window and door frames.

Repair torn screens

Make sure that screens are tight fitting in the window frame, and they do not have any tears.

Keep attic doors and fold-down stairs closed during winter months. Insects can enter attic spaces through soffits, later entering the livable space when they are attracted to lights and heat.

Who wants to be a bee? I don’t claim to know the deepest desires of insects that visit our gardens and farms, except that they want to survive, eat and reproduce. So why do so many mimic other insects that are dangerous, such as yellowjackets? The black and yellow stripes of a typical yellowjacket are easily recognizable to birds, humans and other mammals and signal “Danger! I sting!”. That’s a pretty powerful message that ensures yellowjackets and other wasps and bees are avoided by hungry predators looking to raid the colony for tasty larvae or honey. It’s called aposematic coloration and serves as a warning to other animals not to mess around. From skunks to poison arrow frogs to snakes, aposematic coloration protects both predator and prey from unfortunate interactions.

But what about the harmless insects that are similarly colored? In landscapes and gardens throughout the U.S. you can look closely and find small black and yellow-striped insects

Hover fly on daisy fleabane.

hovering above flowers. Harmless hover flies (a type of fly in the Syrphid family) display a mimicry of yellowjacket coloration, as you can see in the picture. Adults hover flies feed on nectar and pollen, thereby serving as minor pollinators of many flowering plants. The larvae, or maggots, of some hover flies are saprotrophs (feeding on decaying

matter) and some are predatory on smaller insects, like aphids and thrips. Aphids, alone, cause tens of millions of dollars in crop damage each year. Hover flies are considered among the many important natural enemies of aphids and other plant-feeding pests. A gardener’s friend, indeed!

Also in the Order Diptera (which includes all flies and mosquitoes) are the amazing robber flies. The one pictured is called a bee-mimic robber fly. It closely resembles a bumble bee

Bumble bee robber fly

and enjoys the protection that such mimicry provides. How could you tell it apart from a bumble bee? All flies, including these, have only one pair of wings. Look closely at the image and you can see a round dot at the base of the wing. That is called a haltere, which is a wing reduced into a flight stabilizer. You can also see very enlarged eyes, relative to the head, small V-shaped antennae and a thick straw-like mouth. Yes, robber flies can bite! But they are voracious predators of other insects – whatever they can catch. Although robber flies are indiscriminate about what other insects they eat, if you have a garden with pests and you see robber flies, they are probably doing good deeds for you.

By looking closely at the many insects that visit your yard and garden, you might be surprised at how many beneficial insects you see. Maintaining your green space using fewer pesticides and incorporating IPM strategies to manage plant feeders will help protect these amazing natural enemies.

A common pest in homes is the red-eyed fruit fly: Drosophila melanogaster. Famous for use in genetic studies, and infamous for emerging from store-bought bananas, management of this fly rarely requires more than discarding infested items outside of the home.

A dark-eyed fruit fly adult

Management of this fly’s cousin, the dark-eyed fruit fly (Drosophila repleta), also requires elimination of breeding habitat. However, finding and addressing that habitat can be more difficult. This is because dark-eyed fruit flies develop in wet, decaying organic material that may be out of sight. They are common pests in bars, restaurants, and some coffee shops where they breed under equipment, near drains, sinks, and beverage taps. In these accounts, customers may observe flies near food, drinks or when they rest on walls. Flies may defecate (poop) on walls and leave black fecal spots on otherwise light-colored surfaces, affecting your client’s brand.

Identify the Problem.

When dealing with dark-eyed fruit flies, the first and most important step is a thorough inspection to identify breeding locations. Focus your inspection on places that remain wet, and where food spillage might be present. In addition to sinks and drains, consider moisture from condensation on refrigerators, ice machines and pipes.

Gaps around sinks and drains allow food and moisture to accumulate, providing breeding habitat for fly larvae or maggots.

Over time, tile grout can break down or be removed, especially in commercial kitchens that are wet cleaned nightly. These spaces can accumulate food and hold moisture to create fly breeding habitat.

Address the Problem.

Whether structural or sanitation issues contribute to fly problems, the solution is to remove breeding habitat. Keeping areas dry and free of food spillage will avoid future problems with fly breeding. Some questions to consider: Is there tile grout missing, allowing water and crumbs to accumulate? Is the floor angled or are depressions present that collect water? Does food fall behind or under equipment and is not regularly cleaned? Are floors power-washed at night, lodging food and water in areas that are out of sight or stay wet throughout the day? Are there cracks and crevices near the sink that do not have a sealant?

Quick Fix.

Once a maggot has completely developed, it will crawl out of its moist breeding habitat and find a dry place to pupate. This fly developed in the moist gap below, and is seen here in a corner of the sink.

Addressing structural or sanitation issues are a long-term solution that will prevent fly breeding. But what can be done in the immediate future to address customer concerns? Dark-eyed fruit flies are attracted to insect light traps, which can be installed in kitchen areas. Traps may also be placed out at night when all other lights are off to harvest active flies. In addition, fans can be used to dry out breeding areas or to keep flies out of customer spaces.

What NOT To Do.

Bug bombs and general pesticide applications do nothing to address the breeding fly population, and therefore do nothing to prevent future problems. Similarly, pest-strips containing dichlorvos are sometimes used illegally for management of fruit flies in restaurants. According to the label, these products are intended for use in confined spaces where people are present for no more than four hours at a time. They are not to be used in areas where food is prepared, stored or consumed. For more information on pest-strips, see our previous post, Pest-Strips: A Kitchen No-No!

It’s tiny, but it packs a wallop. That’s SWD — spotted-wing drosophila — a new invasive fruit fly that’s put down roots in nearly every berry-growing region in North America. Losses can range from “lots” to “entire crop wiped out.” In New York alone, that’s millions of dollars down the drain.

CBS2’s Vanessa Murdock reported from the field, interviewing growers and scientists who seek an answer to this menace — along with up-close-and–personal footage of the damage it wreaks.

Your kitchen-variety fruit fly likes overripe or rotting fruit. But SWD zeros in on fresh fruit. And often you can’t see the damage till after you’ve harvested your crop. Which means you can’t market it.

“Growers are losing tens of thousands of dollars on a per-farm basis,” said Cornell scientist Peter Jentsch.

When a pest problem begins in an office or workshop, it might seem like the entire place is overrun. But more often the pests are feeding and breeding in just a few confined areas — making there way from there to other parts of the building. Pest managers call this the 80/20 rule, meaning that 80 percent of pest problems come from 20 percent of the area.

These two cases highlight the 80/20 rule:

Case One. The scene — a small office in a corporate building. What started as a few flies in the waiting room quickly escalated to hordes of flies around computers, lights, equipment — and guests — in every part of the office. These were Phorid flies — small, 1/8 to 1/4 inch long, but annoying nonetheless. How to ID them? For starters, they’re humpbacked and their wings have distinctive veins. They like to breed in rich organic material.

Our inspection took us to a part of the building that had been vacated several months prior — and we quickly found our problem’s source in an empty office, where swarms of flies surrounded a closed trashcan.

That brownish stain — that’s where old food dripped onto the floor after a fridge was emptied and the office vacated.

Open the lid — and here’s what we saw.

Up close and ugly: flies at work doing what flies do best.

Spillage from the can had dried on the floor. And inside? Thousands of fly larvae and pupae — breeding in food discarded from a refrigerator emptied months before. This single trashcan was responsible for flies throughout the building. The trashcan was bagged and removed, and sticky traps with an attractant captured the flies. Case closed.

Case Two: The scene — a school with an ongoing cockroach problem. Sightings had dropped dramatically over time, but still — building managers wanted to stay ahead of the game with proactive control measures. Our inspection found a few conditions conducive to pests, but none accounted for the large numbers of cockroaches previously seen.

Then — in a tucked-away part of the building, up a ladder and through a closed door, we came to a storage room. The place was littered with piles of frass (insect droppings) — which told us this area had

In a barely accessible storage room, evidence of leaking pipes from days gone by.

And beneath those pipes — evidence left by cockroaches attracted by the three all-in-one biggies: Food. Water. Shelter.

once hosted a large cockroach population. On the floor was dried sewage from an old leaky pipe, one that had recently been replaced. We had found the breeding and harborage site that attracted cockroaches in the first place.

The takeaway? If you have an abundance of pests, remember — the source is often in those areas that are out of sight, difficult to access, or otherwise hard to clean.

Fireflies are out and about, here and there — and when you see them, know that corn rootworms are most likely hatching. If this is year one of a corn rotation, not to worry. Otherwise — scout. Small investment, big returns.

Plant on right: healthy roots. Plant on left: corn rootworm at work.

Stable fly adults — ouch — have emerged via slowly growing larvae from overwintering sites near barns and feedlots. They’re hard at work doing what they do best: biting cattle and horses for the blood meals that females need to lay eggs. It’s “pain, no gain” for cows, which give less milk when bugged by flies.

Potato leafhoppers are blowing in from points south. Keep an eye on your alfalfa (and your potatoes!) — a bad leafhopper year is bad news for your bank balance. Be quick to scout after a storm — the downdrafts that precede each front will drop adults onto your fields. Plant “hairy alfalfa” varieties that leafhoppers don’t like.

Hopperburn on alfalfa — not good for yields or feed value. Scout for potato leafhoppers; plant resistant varieties.

Armyworms, like potato leafhoppers, are long-distance migrants. Adult moths cruise in on northbound storms, but it’s the larvae that pose problems. Some armyworms we saw were diseased — infected by a fungus. Others were parasitized by tachinid fly larvae; the adults dine mainly on flower nectar. Good work by unsung heroes.